Infosec from @rattis' point of view

Category Archives: CIRT

About a month ago, I added a couple shell scripts to my DFIR Github repository. Three of the four scripts are used at work daily in either a Linux terminal, or a Cygwin terminal. The fourth script is something I use to help with quarantined mail, and not really DFIR based.

b64Decode.sh and hexConvert.bash take command line arguments and reports back the result. For example:

The first extractor script, xHttpExtractor.py came about from a web based tool I used. It would run on a file uploaded to it, and then list a bunch of indicators, system artifacts, url calls outs, network communication, etc. However the tool didn’t have a good export mechanism at the time. So I would copy and paste everything to a text file, and then extract the url host details from the text files. Mainly so I could add the URL indicators to the web proxy.

I re-wrote a script I use at work. It was a messy bit of Python 3 previously. While it’s still not the cleanest of python scripts, it scratches my itch. It was originally just a straight line of commands with lots of repeated code. I made some functions and made it a little more modular. I know I need to learn PEP8, and start following it. This was just to improve something that I wrote previously with things I learned from Automate the Boring Stuff with Python.

I’ve shared it via my GitHub repository for DFIR scripts. They’re clean (not tied to any company). There is only Computer Ping for right now. There are 3 scripts all based on the same idea.

Ping a computer, if it is down, keep trying every 10 minutes for 1 hour. Pop an “alert” if the target is up, or the script finished before it came up.

1 version for Windows running python (wComputerPing.py)

1 version for Windows running Cygwin (cwComputerPing.py)

1 version for boxes running Linux. (lComputerPing.py).

I’ll write others and upload to the repository as I have time / re-write stuff I use. They might not all be Python, but my goal is to be more Python than not.

Has anyone else noticed that Bing has lots of Domain Generation Algorithm (DGA) links in the search results? it isn’t on every search, just some searches. But the same search result at Google doesn’t return the DGA links.

So my android phone as an interesting problem, granted it’s an S4, running not the latest build so I don’t know if that problem still exists. Apparently the way the default mail application is set up, it can’t sync the mailboxes unless the Sync button is turned on. But that doesn’t stop that the mail application from trying to sync on a schedule.

I’ve stumbled around with Shodan.io for a while now. It’s a great tool, but using it effectively has always eluded me. John Matherly has given me some great advice on twitter, and I like Daniel Miessler’sShodan Primer. But I never really find the information I need at the time.

While I know it is great to find webcams and spying Super Gnomes, that is just something I don’t use Shodan for. A lot of the reason I use Shodan lately is for work. Usually someone in management asks will if anyone knows what Shodan knows about the company. Which of our systems are listed on there.

Today while stumbling around trying to look up the company name and the netblocks, and using Dan’s cheatsheet (linked above), I noticed a new link on the page. Book.

This link goes to Lean Pub’s “The Complete Guide to Shodan” by John Matherly. It is a pay what you want book. They suggest just under $5.00 USD, for the 60 page booklet. I’m saying it’s worth more than that. I paid $10.00, which I still think is too low for this book.

The book can be delivered to your Kindle or downloaded as a pdf, an Epub, or Mobi file. I grabbed the PDF and Kindle copies of the file (too small to read on my phone and never figured out how to get it to show up in the Kindle Cloud reader).

This book is divided up in to Web Interface, External Tools (like the linux command line), Developer API, Industrial Control Systems, Appendices, and Exercise Solution.

There are exercises at the end of the Web Interface, External Tools, and API sections. Not all of them worked the way they were described in the book. For example I couldn’t find the Rastalvskarn Powerplant, even though it shows up with the link in the solution section.

I’ve read some documents on the API and struggled to get them to work. After reading the book, while I still have some questions, I know I can write the Network Alert that management wants.

Get this book, it’s worth more than anything you’ll pay for it. While it is only just over 60 pages, the content is great! Especially especially the Filter list in Appendix B.

Last week or so, I read the Symantec Security Response blog, talking about Business Email Compromise. Short version it talks about campaigns targeting C-level employees to try and do wire transfers. There were 2 type, one is the CEO emailing another C-level because he’s stuck in meetings and needs a wire transfer. The other version is an acquisition email, that hasn’t been announced yet.

The blog linked above has screen shot examples.

At my day job, I do occasionally work on Phishing emails. While the Symantec article was good, it is missing that the example emails are no longer going to the C-levels. While I haven’t seen the acquisition email yet, I have seen lots of the person in the meeting email going around.

It isn’t just at the C-levels. I’m seeing emails claiming to be from VPs and Directors, to underlings using the same comment about being tied up in meetings and needing the wire transfer done. Where I work the C-levels are good at catching them and reporting to them. The lower levels however have been fruitful targets. Not realizing it is a phishing attempt and trying to comply.